1. Field of the Invention:
This invention relates to receptacles for surgical aspirators and more particularly to disposable containers adapted to receive fluids, tissue and the like aspirated from a surgical site by a surgical aspirator.
2. Description of the Prior Art:
Many intraocular surgical techniques have come to be performed by microsurgery using miniature surgical tools adapted to be inserted within the globe of the eye and provided with cutting means or severing intraocular tissue, suction means for removing this tissue by aspiration and irrigation means for bathing the surgical site in a physiologial fluid and maintaining intraocular pressure. These microsurgical tools are powered and controlled by an electro-hydraulic and electro-pneumatic control system, which is actuated and controlled by the surgeon. Such a microsurgical system, for example, is the System VI manufactured by CooperVision, Inc.
In ophthalmological microsurgery the surgeon uses a handpiece which carries a small-diameter cylindrical surgical tool which is inserted into the eyeball through an incision made in the cornea or sclera. The surgical tool is commonly in the form of a hollow tube and may be provided with a pneumatically operated cutter for severing intraocular tissue. The central channel of the tubular surgical tool is connected to a source of suction which aspirates the severed tissue from the interior of the eyeball. In another embodiment, the surgical tool is comprised of coaxial tubes, and an ocular irrigation fluid is supplied through the outer tube to macerate and flush away tissue from the interior of the eye, while a source of suction is applied to the lumen of the internal tube in order to aspirate the tissue and fluid. In either case, the excised tissue which is aspirated from the interior of the eye, possibly together with fluid aspirated along with the tissue, is collected in a collection vessel of some sort, e.g., a bottle or bag, usually located remote from the handpiece and near the source of suction.
In order to control the operations of the microsurgical tool, a remote control cabinet or console is usually provided which contains a source of suction for the aspirating function of the surgical tool, a source of gas pressure to operate a pneumatically powered surgical cutter, a source of irrigation fluid and control means for controlling the supply of suction, fluid and pressure to the surgical handpiece. The fluid, pressure and/or suction is supplied to the surgical handpiece via flexible tubing connecting the handpiece with the control cabinet.
The control cabinet is also provided with switches for selecting the particular mode of operation of the microsurgical system and with control means to adjust the parameters of the system such as the level of the suction vacuum and the cutting rate of the microsurgical cutter. The control cabinet also contains means, e.g., solenoid controlled valves, for turning the fluid flow, suction, and gas pressure on and off. These control valves are actuated under control of the surgeon, generally through the operation of a footswitch.
Two common intraocular surgical procedures are vitrectomy and irrigation/aspiration (I/A). In vitrectomy, portions of the vitreous are severed by a pneumatically-operated reciprocating cutting and the severed tissue is aspirated by suction through the central lumen of the hollow tubular cutter. Accordingly, in vitrectomy procedures, the handpiece must be provided with a source of gas pressure for operating the cutter and with a source of suction for removing the excised tissue. In irrigation/aspiration procedures, the handpiece must also be provided with a source of irrigation fluid. In either case, the aspirated fluid and/or tissue must be collected in a suitable receptacle for disposal.
In any intraocular procedure which involves aspiration of fluid and/or tissue from the interior of the eyeball, it is evident that control of the level of suction is very important in order to prevent damage to the eyeball including possible collapse due to excessive suction. Control of the suction level is set by the surgeon using control means in the control cabinet. However, when the aspiration is shut off by valve means in the control cabinet a residual vacuum remains within the tubes and within the receptacle for aspirated fluid and tissue. Accordingly, when the suction is cut off the suction tube is immediately vented to the atmosphere by a solenoid control vent valve. Accordingly, the pressure within the suction tubes immediately rises to atmospheric pressure, and aspiration of material from within the eyeball is essentially terminated at once.
Because of the rather complex fluid connections required between the control cabinet and the handpiece of an ophthalmological microsurgical system, attempts have been made to simplify the connecting process by incorporating some of the fluid connection manifold within a cassette which incorporated both a collection vessel, means for connecting the various tubes leading to the handpiece and internal tubing connections for connecting and controlling the suction source, the vent, and the irrigation fluid. Such a microsurgical cassette is disclosed in Cook, U.S. Pat. No. 4,493,695. The microsurgical cassette receptacle therein disclosed fits into a location in the control cabinet where it is releasably held by a latch. The control cabinet has connectors for a source of suction and for a controlled vent valve which mate with corresponding connectors on the cassette. The control cabinet is also provided with controllable occluders which can press on the tubing manifold within the cassette to control the flow of irrigation fluid and to control the suction. However, this cassette does not include means for controlling gas pressure for powering a vitrectomy cutter. If the cassette becomes filled with aspirated material during the surgical procedure, the cassette must be replaced with an empty cassette or removed from the console, emptied and put back into the console. This process interrupts the operation.
Accordingly, a need has continued to exist for an improved surgical suction cassette.